Invasive fungal sinusitis in immunocompromized patients is rare but fatal infection. Aggressive antifungal treatment is mandatory but it is not without risk. Caspofungin, an echinocandin antifungal agent, is active against aspergillus and candida infections. It works on cell wall synthesis without affecting mammalian cells hence minimal toxicity. We report here a case of invasive aspergillus sinusitis invading the apex of the right orbit and compressing the optic nerve in a kidney transplant recipient with diabetes mellitus. He was treated with transnasal endoscopic decompression of the optic nerve and started on ambisom (Liposomal amphotericin B) for 2 weeks when he developed both renal and hepatic dysfunction without clinical improvement. Caspofungin was introduced and given for 6 weeks. The patient recovered clinically, radiologically, hisologically and microbiologically with normalization of both kidney and liver functions while on cyclosporin. Invasive fungal sinusitis in immunocompromized patients has to be treated aggressively both surgically and medically. Caspofungin is a safe antifungal drug even with the use of cyclosporin.